marketers as
a) consumers
With empowered consumers, or like trendwatching calls them in their briefing SELLSUMERS, the future smiles to those who can help consumers become marketers.
The web is a platform, a means to an end, and applications that help people create, showcase, share and finally sell their own products and stories are springing. See Threadless—Blurb—Lovely Charts—Springspotters-the Doritos Superbowl Ad contest, etc.
b) traditional communications professionals
On a slightly different note, in this age of participation there is a very heavy involvement of advertising, marketing and communications professionals in the conversation. Their voices are already heavily represented on sites like blogger-slideshare and twitter, social media has an amplifying effect for them. Whether this is fair or not for the true-consumer it's undeniable that it represents more opportunity. And so business like the Chartbeat-Veer-iStock- creative circle and so continue to succeed.